Electrical interlock



Aug. '16, 1932. R s LE I ELECTRICAL INTERLOCK Filed Oct. 2. 1929 ATTORNEY,

Patented Aug. 16, 1932 1 UNITED,- STATES;

PATENT- OFFICE ROBERT s. :enELLE, or norms, mj'w YORK, AssioNoR TO THE nnELLE. COMPANY, or

' B OOKLY mew YORK, A conromr on or NEW YORK ELEQTRI'CAL m'mnnoox I App1'icatitn filed October 2, 1929.. serial lio. 39.6;79d-

My invention relates to electrical interlocks, and more particularly to; an attachment of this characterespecially adapted for use upon dumbwaiter doors in which the lock bar not only cooperates with a latch memher, but actuates the switch mechanism for controlling the"-power for operating the dumbwaiter. I

Electrical interlocks of various types have long been in successful operation, and the general function of such mechanisms is well known.- However, not only does the con struction of such interlocks vary with different constructions and difierent types, of doors, but local requirements or particular uses satisfied by one type of-interlock,may not be satisfied by another type.

The interlock of my present invention was produced to meet! conditionrequiring'the positive mechanical'locking of a dumbwaiter door, and the closing'of the circuit to the dumbwaiter operating motor, at all times excepting when'the dumbwaiter car is a'djacent the opening closed by a door. The construction of the lock oiimy invention is such as to compel a substantially complete closure of the door before power can be applied to the dumbwaiter, and to establish a relation of the latch member and the latch bar prior to the actuation of the switch mechanism, which will preclude any possibility of the door being left in a position to eflect the closing of the switch mechanism, and permit subsequent movement ofthe door sufficient to allow access to the dumbwaiter car.

By this construction it is impossible, while a dumbwaiter is in motion, for anyone to exercise any control over the dumbwaiter car so as to have access thereto, except during that short interval while the latch mechanism is released-by the striker orcam carried by the car. i i

The shafts for duin'bwaiters are ordinarily of small dimensions, and equipment in shaft where dirt may readily accumulate thereon, I so construct the actuating lever of the switch mechanism that it may have the desired range of movement to ensure reliability in the actuation of the circuit control switch, and at the sametime expose, upwardly of the'shaft, no spaces about this actuatingmember sufiicient to permit dirt to enter the housing in suflicient quantity to interfere'with the proper action of the switch mechanism.'-

The switchof my invention is so constructed as to not only afford the desired strength and durability of-parts necessary in a mechanism subject to the severe usage which automatic devices of this character receive, but its construction and operation are such thatlikelihood of interference with the operation of the dumbwaitercar is reduced to a minimum, by reason of the short interval of time allo'wed for what may be termed the illicit control of the dumbwaiter, and the impossibility of getting access to the dumbwaiter by an improper use of the door, even though the power to the dumbwaiter be interrupted.

The invention consists primarily in an electrical interlock embodying therein a housing having a slot'in the top thereof, fixed elec-' trical contacts within said housing, a vertically extending rocking lever, one arm of which carries aspring pressed movable contact, and the other arm of which projects through said opening in, and extends above, the top of thehousing a spring operative upon said lever having a normal tendency to disengage said movable contact from said fixed contacts, a vertically extending rocking latch lever pivoted exteriorly of said housing, and extending upwardly beyond said first named rocking lever in a vertical plane parallel therewith, an impact member car- 9 ried thereby, a horizontally extending latch bar carried by and movable with a vertically movable door section and a spring operative upon said latch lever with a normal tendency to engage it with said latch bar, a cam member carried by said latch bar in engaging relation with said switch actuating lever, said latch bar being engagea-ble by said latch lever to mechanically lock the dumbwaiter door before said cam is-operative upon said rocking lever to engage said electrical contacts and a striker member carried by and movable with a dumbwaiter car co-operatmg with said impact member to cause the engagement and disengagement of said latch lever with said latch bar according to the position of the dumbwaiter car; and in such other novel features of construction and combination of parts as are hereinafter set forth and described, and'more" particularly pointed out in the claims hereto appended.

Referring to the drawing,

Fig. 1 is an elevation of a fragmentary portion of a counterbalanced elevator door adjacent the meeting line of the two sections with an electrical interlock embodying the invention applied thereto, the cover of the housing being removed; r Fig. 2 is a view thereof. from the left'of Fig. 1 showing the striker or cam carried by and movable with the dumbwaiter car, and illustrating in dotted lines the locked and unlocked position of the mechanical locking means embodied in the interlock; I

i. Fig. 3 is a plan view of Fig. 1 with the housing cover in position;

Fig. t is a fragmentary portion illustrating the latch bar and the parts co-operating therewith when the door is in the partially open position; and I Fig. 5 is a similar view illustrating the relation of parts shown in Fig. 4, with the latch in'posit-ion to close the switch mechanism, and yet permit the door to be raised sufiiciently to actuate said switch mechanism to open the circuit to the dumbwaiter operator mechanism. 7 Like numerals refer to like parts throughout the several views. 7 r

In the embodiment of the invention shown in the drawing, a portion of the upper section of afcounterbalanced dumbwaiter door is shown at 10, and a-portion of the lower section thereof at 11. These two sections are movable upon vertically extending guides 12, withinthe dumbwaiter shaft, and havejmovement in the same vertical plane toward and from each'other when opening or closing the door. At 13 I have shown a 1 part of theconnections between the two sections. V

Dumbwaiter doors of the character to which my invention relates, are old and well known in the art, and a further description thereof is therefore unnecessary.

The dumbwaiter car itself and the means for controlling the movements thereof, aside fromthat control by the doors through the actuation of the electrical interlock, formno partof the present invention, and requires no detailed description beyond that 'thecontrol for the motive power for such cars must be electrical in order to permit the use of the type'of interlock herein referred to.

:Frequently, such dumbwaiter equipment is so constructed that the controls for the power for actuating the car, may be so set as to cause a car to be moved to, and stopped at, a particular shaft opening, and the electrical interlock of my invention is so constructed and designed as to permit the opening of a door only while the dumbwaiter car is at rest adjacent the opening closed by that door, and to prevent the interruption of power for actuating the car by the opening of the door at any opening other than, what may be termed, the final destination of the car, and access to the car in the event of an attempt to open a door. This will more fully appear hereinafter.

. The electrical interlock of my invention embodies a housingl i, which for convenience in wiring the interlock, is provided with a removable closure 15. Within this housing are fixed contacts 16 and17 arranged in the circuit controlling the movements of the car.- The housing 14 has an opening 18in the top thereof. j

'Pivotally mounted within the housing 14 is arocking lever 19, this lever being mounted upon a horizontally extending pivot'20. The lower arm of the lever 19 carries a stud 21, upon which is slidably mounted a bridge contact member 22 cooperating with the fixed contacts 16 and 17. The stud 21 carries a stop pin 23 adjacent its end, and is encircled by a spring 24 bearing against the lever 19 and against the bridge contact member 22. The contact members 16, 17 and 22 are properly insulated in relation to their supports to avoid short circuiting. ,The other arm of the lever 19 projects through the opening 18 in the top of the housingl l, and has a close sliding fit with the side walls of this opening. The top of this arm is bevelled as indicated at 25 One arm of the lever 19 is acted upon by a spring 26 having a normal tendency to rock said lever in a manner to disengage the contact 22 from the contacts 16 and 17.

Carried by or formed upon the lever 19 is a shield member 27 of a width to close the major portion of the opening 18 which, when a door is opened, results fromthe movement of the upper part of the lever 19toward the wall of theshaft. The top of the housing 14 is provided with, a flange 28 bevelled to permit movement of the shield member, and of a thickness and depth to facilitatethe attachment of the closure 15' to the housing.

The housing 14 is spaced away from the guide rail structure 12 by means of a bridge 29 to which the housing is secured in any desired manner. This bridge carries a pivot screw 30 mounted upon which is a latch lever 31 projecting above and below the housing 14. The lower arm of this lever is provided with the usual adjustable roller impact member 32, adapted to be engaged by a striker or cam 33 carried by and movable with the dumbwaiter car. fThe other arm of this lever is provided with a latch member 34 having't'wo parallelshoulders 35 and 36, the former of which is;

so positioned as .to become operativeprior to, the engagement of the, switch members 16, 17 and 22, and the latter of which is adapted to become operativefollowing such engagement.

The purpose for this will morefully appearhereinafter,

. Carried adjacent the bottom of the upper door section is a latch bar 37, a portion of and the switch lever 19. g Adj acent said lever,

the latch bar 37 is provided with a projecting cam or striker member 39 adapted to engage the bevelled dog of said arm 19. The'dimensions of this striker member are such as to be positioned fairly closely tothe top of the housing 14 and extend over the exposed portion of the slot 18 when the door is in the closed position. 7

Thedepthjof the bar 37, the formation of the striker member 39 and the location of the shoulder 35 are such that toward the final closing movement of the door, the shoulder 35 passes over the top of the latch bar: 37 before the cam 39 has oscillated the lever 19 to an extentto engage the contact 22 with the contacts 16 and 17. As the door reaches the fully closed position, the striker member or cam 39 will have oscillated the lever 19 to an extent to properly engage the contact 22 with the contacts 16 and 17 ,and the shoulder 36 will have passed over and engaged the, lock bar 37. p I

The latch lever 31 is acted upon by a spring 40, the function of which is to, move the latch lever in a direction to engage the latch member 34 with the lock bar, and toposition the impact member 32 in the path of movement of the striker member or cam 33 upon the car.

The operation of the herein described electrical interlock is substantially as follows All of the dumbwaiter doors in a shaft should, at all times, except when access is to be had to the dumbwaiter car, be closed and locked, and the opening of any door from the floor of a building, should be'prevented except when the car is opposite the opening at a particular floor.

Dumbwaiter doors of the-type to which my invention relates, are generaly used in public, or quasi-public, buildings, such as hospitals, schools, churches, restaurants, hotels, apartment houses, etc, and the character of the dumbwaiter installation is usually such that the point of stoppage of the car may be coutrolled at the time that power is appliedto the car. v

With installations of the characterabove referred to, the electrical interlock of my invention is used for the purpose of preventing power being applied to the dumbwaiter car while access is being had thereto, and to pre-' vent the interruption of such power from floors other than that for which the contents of the dumbwaiter are intended: It has nothing to do with controlling the operation of the car, beyond the negative function above referred to; 4

Under some'conditions, persons for whom; the, contents of the dumbwaiter are not in'-- tended, may attempt to so handle the-doors as to permit them to interrupt the power-to the car operating mechanism, and one ofthe purposes of the present invention is to so construct the interlock as to deter thispractice by preventing access to the car, even though it may be stopped at an openingclosed by a door, the theory being that nobody is going to interfere with the operation of the dumbwaiter unless access can be had theretoafter such stoppage.

Assuming that all of the doors in a shaft.

are closed, all of the switches 16, 17' and 22 in the shaft will also be closed, and power may be applied for raising or lowering the dumbwaiter car.

When a door is properly closed and locked, the postion of parts is as shown in Figs 1, 2'and 3. As the car reaches the fioor at which it is to stop, the striker member or cam 33 engages the impact member 32fan'd rocks the latch lever 31 to the position shown in dotted lines in Fig. 2, both shoulders 35 and 36 being moved out of the path ofthe latch bar 37. The parts remain in this position so long'as the car is at rest, thus permit ting the door to befreely opened.

With the initial upward movement of the.

door, the striker member orcam 39, passes from its engaging and restraining relation with the switch lever 19, permitting the spring 26 to rock this lever in a manner to movethe contract member 22 out of engagement with the contacts 16 and 17, thus interrupting the circuit to the dumbwaiter car control. So long as the parts are in this position, which isindicated in Fig. 4, power cannot be applied to cause movement of the car. The quantity of movement, of .the striker member or cam 39, while engaging the bar 19 to thusinterrupt the power for actuating the car, is approximately half an inch;

'If it were not required to make equipment of this kind as nearly foolproof as possible,

a single shoulder 36 could be used upon the e latch member. The difliculty is that those using the dumbwaiter, as experience has demonstrated, are very apt, to serve. their personal convenience, to interfere with the service. Where a lock is accessible from the floor side, and an interlock is used, persons are apt to try to stop the car at a particular opening when the contents of the car'are designed for others at another opening. Where, as in the present case, the interlock V the use of the shoulder 35.

and lock are full automatic, and'located within'the'shaft where they are'not accessible from the floor, such a person will endeavor to instantlyopen the door while the; striker or cam 33 'is operative uponthe latch member 31. This interval, however, is very short, since the operative surface of thecam 33 may be only an inch or two and the dumbwaiter car has fairly high speed. Consequently, in closing the'door, a person trying'to, what is known as steal the car, will endeavor to move the upper section 10 downwardly to an extent to-close the circuit throughthe contacts; and yet not have the mechanical latch memberoperate to lock the door.

'With this condition, were it not for the shoulder 35, itwould'be possible, by a fairly slow movement of the door, to open the door and stop the car entirely independently of an actuation of the'latch member by the striker orcam 33. The shoulder 35 is used so that the mechanical locking of' the door will be assured upon the switch bar 19 being actuated to an extent to engage the contact 22 and. the contacts-16 andli', and hence the door will be mechanically locked upon power being applied to the car to 'move it. This condition is shown in Fig.5. 7 It is' impracticable, 'in equipment of'the character to which'my inventon relates, to so nicely construct and adjust the-parts as to avoid a certain amount of leeway or lost motion not desirable in the device, but necessary because of conditions surrounding devices of; thischaracter. In the device of the present application, there is a leewayofapproximately a quarter of an inch before the engagement'of the shoulder 36 withthe latch bar, during which the circuit to the elevator controls are closed, and this'leeway is what a user might take advantage of, were it not for It will be noted, by reference to Fig. 5 of the drawing, that while the latch bar is not engaged with the shoulder 35, it is also not engaged with the shoulder 36, and that the contact, member 22 is not engaged with the contacts 16 and 17. Slight additional down-- ward movement of the door, not enough to cause the engagement of the shoulder 36 with the latch bar 37,'will nevertheless cause the engagement of the contact 22with the 0011- tactslG and 17. It will also be noted that this condition will permit the opening and closing of the circuit to the power for actuating the car. i

' When the door has been thus moved downward slightly, without engaging the shoulder 36 with the latch bar 37, it may be restored to the position shown in Fig; 5 at any time,'and' thus actuatethe movable contact memberto interrupt the power to the car. By reason of the engagement of the bar 37 with the shoulder35, however,-even though a person might succeed in stopping the car, the door cannot fixed electrical contacts within substantially continuous barrier above said" opening 18, so that in washing down or painting the shaft, or in the event of matter drop ping from the car platform, foreign substances will be excluded from the housing 14.

The use of therocking lever 19'and the actuating striker or cam 39 co-operating there with, not only ensures a positive actuation of the switch mechanisin, but minimizes the a tendency toward a rebound of the door to an extent to avoid a possible failure of the shoulder 36 to engage the latch bar 37.

lever 19 passing.

It will be noted that tampering with the interlock is impossible, sinceit is located within the shaft, and access cannot be had thereto while the door-is closed, nor while the door'is open, since the side walls of the dumb waiter car will prevent such access being had to the interlock while the door is open, and the door cannot be opened unless a car is so located as toprevent such access. If a skeles ton car should be'used, which ordinarily is not the practice, tampering with the interlock would serve no useful purpose, since with dumbwai'ter doors, thepermanent blocking of the lever 19 when the circuit is closed by the switch mechanism controlled thereby, would not aid in securing access to the car, but rather defeat this object.

'An interlock embodying the invention is particularly adapted for use under those con ditions where a positive mechanical looking of the door is required before the circuit controlling the operation of the car is closed, this being secured by the presence of the shoulder may be varied without departing from the.

spirit and scope of the invention.

Having described the invention, what I' claim as new and desire to have protected by Letters Patent, is V i 1. An electrical interlock embodying therein a housing having a slot in the top thereof, said housing, a vertically extending rocking lever, one arm of which carries a spring pressed movable contact, and the other arm" of which projects through said opening in, and extends'above,

the top of the housing, a spring Operative upon said lever having a normal tendency to disengage said movable contact from said fixed contacts, a vertically extending rocking latch lever pivoted exteriorly of said housing and extending upwardly beyond said first named lever in a vertical plane parallel therewith, an impact member carried thereby, a latch bar carried by and movable with a vertically movable door section and a spring operative upon said latch lever with a normal tendency to engage it with said latch bar, a cam member carried by said latch bar in engaging relation with said switch actuating lever, said latch bar being engageable by said latch lever to mechanically lock the dumbwaiter door before said cam is operative upon said rocking lever to engage said-electrical contacts, and a striker member carried by and movable with a dumbwaiter car cooperating with said impact member to cause the engagement and disengagement of said latch lever with said latch bar according to the position of the dumbwaiter car.

2. An electrical interlock embodying therein a housing having a slot in the top thereof, fixed electrical contacts within said housing, a rocking lever, one arm of which carries a spring pressed movable contact, and the other arm of which projects through said opening in the top of the housing, a rocking latch lever pivoted eXteriorly of said housing, said latch lever having a plurality of spaced parallel shoulders, an impact mem ber carried thereby, a latch bar carried by and movable with a vertically movable door section, and a cam member carried bysaid latch bar in engaging relation with said switch actuating lever, said latch bar being engageable by one of the shoulders of said latch lever to mechanically lock the door prior to the engagement of said movable contact with said fixed contacts, and by the other of said shoulders after such engagement.

3. An electrical interlock embodying therein a housing having a slot in the top thereof, fixed electrical contacts within said housing, a rocking lever, one arm of which carries a spring pressed movable contact, and the other arm of which projects through and has a close sliding fit in said opening in the top of the housing, a rocking latch lever pivoted exteriorly of said housing, an impact member carried thereby, a latch bar carried 7 by and movable with a vertically movable door section, and a cam member carried by said latch bar in engaging relation with said switch actuating lever, said cam member being of dimensions to shield the portion of said slot resulting from the actuation of said lever, said latch bar being engageable by said latch lever to mechanically lock the dumb,- waiter door.

4:. An electrical interlock embodying therein a housing having a slot in the top thereof, fixed electrical contacts within said the other arm of which projectsthrough and has a close sliding fitin-smd opening" in the top of 'the housing, a. shield carri d by and movable with said rockinglever, the dimensions of which are such as to substantially close the portion'ofthe slot exposediby the movement of said lever when a door is open,

a rocking: latchlever pivoted exteriorly of said housing, an impact member carried thereby, a latch bar carried by and movable with a vertically movable door section, and a cammember carried by said latch bar in engaging relation with said switch actuating lever, said cam member being of dimensions to shield the portion of said slot resulting from the actuation of said lever, said latch bar being engageable by said latch lever to mechanically lock the dumb-waiter door.

5. An electrical interlock embodying therein a housing having a slot in the top thereof, fixed electrical contacts within said housing, a rocking lever, one arm of which carries a spring pressed movable contact, and the other arm of which projects through and has a close sliding fit in said opening in g the top of the housing, a rocking latch lever pivoted exteriorly of said housing, said latch lever having a plurality of spaced parallel shoulders, an impact member carried thereby, a latch bar carried by and movable with a vertically movable door section, and a cam member carried by said latch bar in engaging relation with said switch actuating lever, said cam member being of dimensions to shield the portion of said slot resulting from the actuation of said lever, said latch bar being engageable by one of the shoulders of said latch lever to mechanically lock the door prior to the engagement of said movable contact with said fixed contacts, and by the other of said shoulders after such engagement.

6. An electrical interlock embodying therein a housing having a slot in the top thereof, fixed electrical contacts within said housing, a rocking lever, one arm of which carries a sprlng pressed movable contact, and

the other arm of which projects through and has a close sliding fit in said opening in the top of the housing, a shield carried by and movable with said rocking lever, the dimensions of which are such as to substantially close the portion of the slot exposed by the movement of said lever when a door is open,

a rocking latch lever pivoted exteriorly of 7 said slot resulting from the actuationof said lever, said latch barbeing engageableiby one .ofthe shoulders of said 'latchlever tomechanically lock the door 'prior to the engagement of saidmovable contact with said fixed contacts, and by the otherof said shoulders after such engagement. 7 I In Witness whereof I have hereunto aflixe my signature, this 28th day'of September, 1929- r 10 I e 1 ROBERT -S. PEELLE.

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